I-SCAN: Risk of colorectal cancer in inflammatory bowel disease

Risk of colorectal cancer in inflammatory bowel disease

– a multinational cohort study.

Photo: Colourbox

About the project

I-SCAN (IBD – Scandinavian CANcer in IBD study) is a collaborative effort between the Clinical Effectiveness Research Group at the University of Oslo, Karolinska Institutet in Stockhom, Sweden, and Center for Clinical Research and Prevention at Bispebjerg and Frederiksberg Hospital in Denmark. Principal investigator (PI) is Mette Kalager and national PI’s are Weimin Ye in Sweden and Tine Jess in Denmark. I-SCAN also collaborates with Miguel Hernan at the Harvard T.H. Chan School of Public Health in Boston, U.S.

General aim

The current project will provide new cancer risk estimates for patients with Inflammatory bowel diseases (ulcerative colitis and Crohn’s disease). This will enable us to implement effective and cost-effective treatment and surveillance strategies for these patients.

Specific aims

To quantify overall cancer risk among patients with IBD, modified by age at diagnosis, extent of disease, follow-up time and pharmacological treatment.

To quantify the effect, if any, of IBD therapies on the risk of cancer

To develop and validate a prediction model for colorectal cancer risk in IBD patients.

Background

Inflammatory bowel diseases (ulcerative colitis and Crohn’s disease) – are the most common non-malignant chronic diseases affecting the large bowel.

Patients with inflammatory bowel disease, and notably those with ulcerative colitis, are at increased risk of developing colorectal cancer. In 1990, we published the first large-scale population-based prospective study of cancer risk among patients with ulcerative colitis and Crohn’s disease.1,2 At least two factors might have modified and indeed reduced their cancer risk. Firstly, improved pharmacological treatment such as immunomodulatory agents (thiopurines and tumor necrosis factor-alpha antagonists).3,4 Secondly, patients with inflammatory bowel disease are more extensively and systematically under colonoscopic surveillance with biopsies and even prophylactic colectomy. Such surveillance may reduce risk of colorectal cancer. However, although multiple studies have tried to update our findings from 1990, their estimates remain uncertain because of challenges in design, size, methodology or reliable data access.5,6 Therefore, it is currently unclear to which extent the results published in 1990 are generalizable to patients treated for inflammatory bowel disease today.

The current project includes unique, large-scale studies to disentangle the risk of cancer in patients with inflammatory bowel disease in our current, modern era of medicine. Prerequisites for this project may exist only in the Nordic countries due to their excellent infrastructure for epidemiologic research. We also take advantage of the great experience we have within the research consortium of this project, which has proven to produce cutting-edge scientific results of this magnitude and novelty in the past.7-9

Registry-based research

We intend to develop the largest ever population-based cohort of patients with incident IBD (ulcerative colitis or Crohn’s disease). This project is possible because of the characteristics of health data collection in Scandinavian countries, which are uncommon in the rest of the world (Figure 1). We will collect data on all patients with IBD in Norway, Sweden and Denmark from 1970 until today. We aim to link multiple data sources, including high quality, virtually complete, nation-wide registers of cancer incidence (Cancer Registry), in-patient care (Patient Registry) (with codes for surgical procedures and all discharge diagnoses), prescribed drugs (Prescription Registry), immigration (Population Statistics), and dates as well as causes of death (Death Registry) (figure 1). Combination of these data sources gives detailed follow-up data that enable us to achieve our ambitious aims.

Financing

The study is funded partly by grants from the South East Regional Health Authority in Norway.